Efficient clay supported Ni0 nanoparticles as heterogeneous catalyst for solvent-free synthesis of Hantzsch polyhydroquinoline

A green and efficient multicomponent one-pot synthesis of Hantzsch polyhydroquinoline was achieved by the condensation of aldehydes, dimedone, ethylacetoacetate and ammonium acetate at room temperature using environmentally benign modified Montmorillonite supported Ni0-nanoparticles as catalyst. The well dispersed Ni0-nanoparticles having a high surface to volume ratio have promising features for the reaction such as easy removal of the catalyst, solvent-free, shorter reaction time, high product yields (about 95%) and easy work up procedure. There is no significant effect of electron withdrawing or donating nature of substituent on aldehydes in the formation of polyhydroquinoline derivatives.

► Modification of Montmorillonite clay by mineral acid activation.
► In-situ generation of Ni0-nanoparticles on modified Montmorillonite clay.
► Hantzsch polyhydroquinoline synthesis by the supported Ni0-nanoparticle catalyst.
► The synthesis involves no solvent, easy work up and exhibits high yields.